From 5340215304193f18af3bc76c7ae7a6a79f008339 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Wed, 11 Mar 2020 14:58:05 +0100
Subject: Implement a hash function to calculate FIG 0/7 Count field

This might not be strictly standards compliant, but it avoids having to save state
across mux restarts and doesn't place the burden of incrementing the number on the
operator.
---
 src/DabMultiplexer.cpp | 87 +++++++++++++++++++++++++-------------------------
 1 file changed, 43 insertions(+), 44 deletions(-)

(limited to 'src/DabMultiplexer.cpp')

diff --git a/src/DabMultiplexer.cpp b/src/DabMultiplexer.cpp
index 2bd8d74..5eca126 100644
--- a/src/DabMultiplexer.cpp
+++ b/src/DabMultiplexer.cpp
@@ -31,41 +31,6 @@
 
 using namespace std;
 
-// Protection levels and bitrates for UEP.
-const unsigned char ProtectionLevelTable[64] = {
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 2, 1, 0,
-    4, 3, 1,
-    4, 2, 0
-};
-
-const unsigned short BitRateTable[64] = {
-    32, 32, 32, 32, 32,
-    48, 48, 48, 48, 48,
-    56, 56, 56, 56,
-    64, 64, 64, 64, 64,
-    80, 80, 80, 80, 80,
-    96, 96, 96, 96, 96,
-    112, 112, 112, 112,
-    128, 128, 128, 128, 128,
-    160, 160, 160, 160, 160,
-    192, 192, 192, 192, 192,
-    224, 224, 224, 224, 224,
-    256, 256, 256, 256, 256,
-    320, 320, 320,
-    384, 384, 384
-};
-
 static vector<string> split_pipe_separated_string(const std::string& s)
 {
     stringstream ss;
@@ -174,6 +139,48 @@ void DabMultiplexer::prepare(bool require_tai_clock)
         }
     }
 
+    if (ensemble->reconfig_counter == dabEnsemble::RECONFIG_COUNTER_HASH) {
+        vector<uint32_t> data_to_hash;
+        data_to_hash.push_back(ensemble->id);
+        data_to_hash.push_back(ensemble->ecc);
+
+        for (const auto& srv : ensemble->services) {
+            data_to_hash.push_back(srv->id);
+            data_to_hash.push_back(srv->ecc);
+        }
+
+        for (const auto& sc : ensemble->components) {
+            data_to_hash.push_back(sc->serviceId);
+            data_to_hash.push_back(sc->subchId);
+            data_to_hash.push_back(sc->type);
+            data_to_hash.push_back(sc->SCIdS);
+        }
+
+
+        for (const auto& sub : ensemble->subchannels) {
+            data_to_hash.push_back(sub->id);
+            data_to_hash.push_back(sub->startAddress);
+            data_to_hash.push_back(sub->bitrate);
+
+            uint32_t t = 0;
+            switch (sub->type) {
+                case subchannel_type_t::DABAudio : t = 1; break;
+                case subchannel_type_t::DABPlusAudio: t = 2; break;
+                case subchannel_type_t::DataDmb: t = 3; break;
+                case subchannel_type_t::Packet: t= 4; break;
+            }
+            data_to_hash.push_back(t);
+            data_to_hash.push_back(sub->protection.to_tpl());
+        }
+
+        uint16_t crc_tmp = 0xFFFF;
+        crc_tmp = crc16(crc_tmp,
+                reinterpret_cast<uint16_t*>(data_to_hash.data()),
+                data_to_hash.size() * sizeof(data_to_hash.data()) / sizeof(uint16_t));
+
+        ensemble->reconfig_counter = crc_tmp % 1024;
+        etiLog.level(info) << "Calculated FIG 0/7 Count = " << ensemble->reconfig_counter;
+    }
 }
 
 
@@ -480,20 +487,12 @@ void DabMultiplexer::mux_frame(std::vector<std::shared_ptr<DabOutput> >& outputs
     //  number of channels * 4 octets = nb octets total
     int edi_stream_id = 1;
     for (auto subchannel : ensemble->subchannels) {
-        dabProtection* protection = &subchannel->protection;
         eti_STC *sstc = (eti_STC *) & etiFrame[index];
 
         sstc->SCID = subchannel->id;
         sstc->startAddress_high = subchannel->startAddress / 256;
         sstc->startAddress_low = subchannel->startAddress % 256;
-        // depends on the desired protection form
-        if (protection->form == UEP) {
-            sstc->TPL = 0x10 |
-                ProtectionLevelTable[protection->uep.tableIndex];
-        }
-        else if (protection->form == EEP) {
-            sstc->TPL = 0x20 | (protection->eep.GetOption() << 2) | protection->level;
-        }
+        sstc->TPL = subchannel->protection.to_tpl();
 
         // Sub-channel Stream Length, multiple of 64 bits
         sstc->STL_high = subchannel->getSizeDWord() / 256;
-- 
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